So let’s begin with the introduction. Everything from chip to LCD TVs is made up of semiconductors. But in each of these, the materials differ. They are of three types;

Metals – These are also called conductors. These have low resistivity when compared to semiconductors.

Semiconductors– Silicon, Germanium, etc are elemental semiconductors. (CdS, GaAs- compound semiconductors). These have high resistivity when compared to metals.

Insulators: Like wood, plastic, etc. These are very bad conductors of electricity.

Conduction is phenomena due to free electrons. The free electrons possess more energy. If we have a material and it has a nucleus and around it is crystal. Metals have metallic bonds, semiconductors have covalent bonds and in insulators covalent bonds are present. The bonds are present between two electrons. In the above video, there is a diagrammatic representation which will you understand this even better. The electron having more energy is free electrons and the ones with less energy are bonded.

The last topic discussed in this jee physics lectures is energy bands in a solid. In the above video, there is a graph and diagrammatic representation which help you to understand this entire topic in a better way. The relative energy of electrons is in the upward direction. If the inter atomic distance in the positive direction, after a certain distance there is no inter atomic interaction. It means that they do not exert any force on each other.

This is all about the above physics video. This topic can really get on your nerves if you don’t understand this topic properly, so make sure that you understand this topic perfectly well. Please refer the continuation of this video, in order to complete this topic in a simple and easy way.